1. Field of the Invention
The present invention is concerned with a display device for a camera, which makes indications of exposure informations, etc. within a view-finder or any other designated place.
2. Description of the Prior Art
There have so far been known various meters and liquid crystal elements to be used as the display element in such camera display device.
Since these display elements do not emit light by themselves, their observation is difficult when the surrounding is dark. In order, therefore, to make it possible to read those informations as displayed in the dark, there has been known a display device, in which a lighting device to illuminate the same is incorporated. One type of the display device having this illuminating device is such that the display device is driven by a switch means which is closed during half-depression of a shutter release button and for a predetermined period of time after the shutter button being freed from its half-depressed condition, while the illuminating device is driven by another switch which is closed only during its depression. However, this display device is of such a construction that, in spite of the illuminating switch being closed by its depression, the illuminating device stops its driving as soon as the display element stops its driving after lapse of a predetermined time. That is to say, the display element becomes disadvantageously unable to be observed against the will of an operator who wishes to observe the display element. To overcome this shortcoming, the half-depression of the shutter release button and the depression of the lighting switch may be done simultaneously. However, this simultaneous pushing of the shutter release button and the lighting switch makes it impossible to effect other operations necessary for the photo-taking.
As another type of the display device, there has been known one, wherein both display element and illuminating device are synchronously driven by a switching means which is closed during the half-depression of the shutter release button, and during a predetermined period of time after release of its half-depression. This device is given such a construction that, when the surrounding is bright and no illuminating device is necessary, it is disconnected from the power source by operating a separate change-over switch. By this construction, the above-mentioned shortcoming in the display device is overcome. Nevertheless, when the surrounding is bright, the light from the lighting device becomes not so conspicuous to the operator, which often causes him (or her) to forget to operate the change-over switch, and to continue the photo-taking operation with the lighting device being turned on, in waste, without noticing it. Since the illuminating device consumes relatively large current for driving an incandescent lamp, LED, and so on, such waste lighting results in curtailment of the life of a battery for the camera with limited capacity.